[LeetCode]8 String to Integer (atoi)

https://oj.leetcode.com/problems/string-to-integer-atoi/

http://fisherlei.blogspot.com/2013/01/leetcode-string-to-integer-atoi.html

public class Solution {
    public int atoi(String str) {
        // Validations
        if (str == null || str.length() == 0)
    		return 0;
     
        char[] chars = str.trim().toCharArray();
        int len = chars.length;
        
        int i = 0;
        
        // Check +/-
        boolean negative = false;
        if (chars[0] == ‘+‘)
        {
            i++;
        }
        else if (chars[0] == ‘-‘)
        {
            negative = true;
            i ++;
        }
    
        double result = 0;
        for (; i < len ; i ++)
        {
            char c = chars[i];
            if (c >= ‘0‘ && c <= ‘9‘)
                result = result * 10 + (c - ‘0‘);
            else
                break;  // Break the loop when meeting invalid chars.
        }
        
        if (negative)
            result = -result;
            
        if (result > Integer.MAX_VALUE)
            return Integer.MAX_VALUE;
        if (result < Integer.MIN_VALUE)
            return Integer.MIN_VALUE;
            
        return (int)result;
    }
}

[LeetCode]8 String to Integer (atoi)

原文：http://7371901.blog.51cto.com/7361901/1598404